The phylogenetic position of Haematommataceae (Lecanorales, Ascomycota), with notes on secondary chemistry and species delimitation

The phylogenetic placement of Haematommataceae was studied using newly obtained DNA sequences from nu LSU and mt SSU genes of four Haematomma species, including the type species H. ochroleucum, and a selection of Lecanoromycete taxa obtained from Genbank. The distinction of the family from taxa previously placed within Haematomma but separated on morphological and chemical evidence, such as Loxospora (Sarrameanaceae; syn. Loxosporaceae) and Ophioparma (Ophioparmaceae), is supported. The latter two families cluster outside Lecanorales, while Haematommataceae has an unsupported sister-group relationship to a clade including Lecanoraceae, Stereocaulaceae, and Cladoniaceae within Lecanorales. Placement of Haematommataceae in Lecanoraceae sensu stricto (excluding lecideoid taxa) is significantly rejected in our studies. ITS sequences support the distinction of H. accolens and H. flexuosum, which form a pair of morphologically identical chemomorphs, but do not provide conclusive evidence about species concepts based on chemical differences in this genus.